Abrasive flux and flush control system for dental apparatus



P. J. TASCHER ABRASIVE FLUX AND FLUSH CONTROL March 3, 1959 SYSTEM FOR DENTAL APPARATUS v 2 Sheets-Sheet 1 Filed Sept. 16, 1954 LII III In H INVENTOR. 'PAUL J. 7256/4151? ATTORNEY,

March 3, 1959 P. J. TASCHER 2,875,521

ABRASIVE FLUX AND FLUSH CONTROL SYSTEM FOR DENTAL APPARATUS Filed Sept. 16, 1954 2 Sheets-Sheet 2 To POWER SUPPLY FOR HANDPIECE INVENTOR. PAUL J.TA$CHER United States Patent ABRASIVE FLUX AND FLUSH CONTROL SYSTEM FOR DENTAL APPARATUS Paul J. Tascher, Glen Cove, N. Y.

Application September 16, 1954, Serial No. 456,582 7 Claims. or. 32-58 My invention relates to methods and devices controlling the flux of an abrasive-liquid suspension and water as a flush to the field of dental operation.

The introduction of the use of the ultrasonic dental handpiece as a means of operating on teeth for the preparation of cavities and crowns has presented the need for a method of conveniently bringing to the field of dental operations, a suspension or" water or other fluids with abrasive materials. The principles of operation of the ultrasonic dental handpiece require the continuous presence of water or other fluid as a coolant, and that of an abrasive-liquid suspension which is set into rapid vibratory motion by the ultrasonic handpiece to accomplish the cutting of hard tooth substance. d

A known characteristic of all abrasive materials such as aluminum oxide and boron carbide is that they settle out of liquid suspensions very rapidly. When it becomes necessary to convey these materials from a stock receptacle to the field of dental operation through hose lines or tubings of fine diameter, these materials will quickly clog these tubings as they settle out of the fluid. A short interruption, therefore, in the continuous flow of abrasive suspensions in the tubings will result in a long interruption in the dental operation in order to clean out or unclog the tubing lines.

It is possible to provide the abrasive at the location ofdental operations in other forms, such as in a paste,

or a dry powder, but its most convenient form for dental purposes is in a water-abrasive suspension.

For the purposes of maximum efliciency to the dental operation, the abrasive should be fluxed directly at the point of contact between the tooth. and the ultrasonic cutting tool. This should be accomplished preferably through the means of fine tubing that can be conveniently attached, to the handpiece wherein it will not interfere with the dentistss normal grasp of the handpiece. Nor should the tubing be bulky or, add appreciable weight to the handpiece. The delivery of the abrasive suspension should be completely automatic so that the operating dentist can give his undivided attention to the cutting procedures. At the same time, it should be controllable in respect to frequency and'volume of operation, which are also under automatic control. All of these requirements would permit the dentist to carry on the tooth cutting operations continuously and without interruption. A further requirement would'provide for a device that controls theflux of water only as a flush as a coolant. This should be accomplished by the same automatic means as the flux of the abrasive suspension. Thus, the dentist would be able to flush the cavity with water to wash away accumulated debris and abrasive to enable him to observe the progress of the operation without the danger of the cutting tool overheating, as results from dry operation. Thus, the dentist would have a choice of visibility of the field of operation and uninterrupted continuation of the cutting operation and without the danger of the ultrasonic cutting tool overheating. t v v 'ice Objects of my invention are, therefore, to make possible the start and interruption of the abrasive and water supply at any time deemed fit by the dentist, and to provide for the control of the flux of abrasive suspension and water for this purpose, which the dentist can operate without interrupting the dental operation.

Other objects of my invention are to provide the flux of an abrasive. liquid-suspension in fine tubings which are not bulky or of great weight, and are suitable for use with the small ultrasonic dental handpiece, which is to be placed in the patients mouth.

Other. objects of my invention provide for the flux of liquid-abrasive suspensions in fine tubings in a form wherein the abrasive material which settles out of the fluid very rapidly, will not clog the fine tubing to cause the interruption of the flow of abrasive to the field of operation.

Other objects of my invention provide fora means of quickly and efliciently unclogging the fine tubings, in the event that the abrasive causes clogging of these tubes. In this eventuality, only a short delay is caused in the dental operation, and the latter may be resumed with a minimum amount of time loss and difiiculty.

Other objects of my invention are to open the flux of abrasive suspension and water with a pedal, to close the flux when the pedal returns to its position of rest, to

return the pedal into the position ofrest automatically when the pressure on the pedal ceases, to position the pedalclose to the switch controlling the ultrasonic handpiece in such a manner that the same foot can be held in aposition during a dental operation in which the ,foot is ready for operating the ultrasonic handpiece switch andthepedal. H

Further objects are to provide controlling means which react to the pedal instantaneously, to make possible a selection between the abrasive-liquid suspension and the water flush by a more Or less extended movement ofonepedal. Still further objectsare to obtain these resuIi s with simple and reliable meanspwithvalves and switches of available types, thereby to provide a device that can easily, quickly, and inexpensively be made, and to provide themeans of accomplishing these operational features ina manner to which a dentist is normally accustomed. I

Still other objects and advantages of my invention will appear from the following description of an exemplifying embodiment of my invention, from the appended claims and from the accompanying drawings. In the drawings: V Fig.1 shows a top plan view of the ultrasonic switch controller and the abrasive andwaterfoot pedal controller according to my invention, the electrical system being only incompletely shown.

Fig. 2 shows a front view of the ultrasonic switch controller and the water and abrasive foot pedal controller of Fig. 1, partly cut away.

Fig. 3 shows a cross-sectional view of the device of Figs. 1 and 2, taken along lines 3--3 of Fig. 1.

Fig. 4 shows a side view, partly broken away, of the abrasive duct system and the water flush system according to my invention, pipe lines being shortened for the sake of a more condensed representation, electric cables being omitted. d

Fig. 5 shows a diagram of the electric current system according to my invention, this circuit system connect ing the abrasive and water foot pedal controllers shown in Figs. 1 to 3 with the duct system shown in Fig. 4.

Fig. 6 shows a diagram of the electric circuit system according to my invention, connecting the ultrasonic switch controller shown in Figs. l- 3 with the ultrasonic dentalunit. j

Figures 1, 2 and 3 are embodiments of the ultrasonic switch and abrasive and water controller. It is recommended here that the ultrasonic switch be constructed so asto operate in the same way that the dental motor controlleroperates, by an horizontal acting lever. The long established habits of the dentist who habitually seeks to turn on his power supply by the movement of his toe in a horizontal are on a lever will, therefore, not require change when operating the ultrasonic handpicce.

Referring to the drawings Figs. 1, 2, and 3, numeral 1 indicates the cylindrical housing of the ultrasonic switch device. At the center of this housing is a cylinder 2 which is attached to a horizontal lever 3 and pivots on a central bolt 4 bearing on the base of the center of the housing. This lever 3 is thus free to swing in a horizontal are by the action of the toe of the dentist. The side walls 5 constituting the ends of the arcuate slot through which the lever 3 swings, act as a limitation to the horizontal swing of the lever. Fixed to the base of the housing are two springs 6 which are mounted in :such a way as to urge the lever 3 towards a central neutral position. Thus, when the dentist presses his toe laterally, it does so against the tension of the spring 6 (as shown in the drawing). When his pressure is relieved, the spring will force the lever to a central position. To the base of the housing 1, two well-known small push button type switches 7 are mounted in such "2,875,521 i V a a position that when the lever 3 .is pressed to the extreme limits of the horizontal arc, it will press the push. button 8 of the switches and thus close the electrical 0 .circuits which these switches control, namely, the circuit to start the ultrasonic handpiece into operation. The two pins 5 mounted on the center of the housing 1 limits the permitting the usual operation of this controller by a right or-left-handed dentist as he is normallyaccustorned or to permit any dentist to operate this controller in either direction to permit him a shift in body weight distribution.

On the rear of the housing 1 is a recess 9 which encloses a female type electrical receptacle 10 provided with electrical connectors 11 which are wired appropriately to the push button switch 7 and the switches 19 and 20m be described below.

This receptacle 10 receives a male type electrical plug 12 fitted with the appropriate number of prongs to plug into the female receptacle. These are appropriately wired to an electrical cable 13 whichconnects to a wired panel within the ultrasonic dental unit.

Referring to Figs..13, the forward part of the housing 1 carries an actuating member pedal 14 which is connected to the housing 1 by twohinges 15 which have an horizontal axis so that the pedal can swing vertically. The pedal 14 is shaped to define a segment of a circle and describes an are which completes a circle from the center of the housing 1. From its lateral view, the pedal curves outward and downward just beneath the lever 3. Along its periphery, the pedal14 laterally extends beyond the arc of the lever 3 so that the pedal 14 is continuously within reach of the toe of the dentist whatever the position of the lever may be. The pedal 14 operates the control for the flux of the abrasive-fluid suspension and the flux of water as a flush.

Beneath the pedal 14, the housing ,1 has a forward extension 16 which, when seenfrom above, has the same outline as the pedal. A leaf spring 17 is affixed to the lower side of the pedal and contacts the extension 16 to support the pedal in the position shown from whichthe pedal can be moved down against the tension of the spring 17. A rod or stem 18 is fixed to the pedal 14 and forms a downward extension of the same.

Two switches are positioned under the pedal 14 and can be operated by the downward movement of this pedal. In the embodiment shown, there are two switches 19 and 20. These switchesfare of the well-known pushbutton type (microswitches) and close an electric circuit when a button 21 is pushed; and are arranged symmetrically under the rod 18 from which the action of these switches is derived by pressure on the pedal 14.

The rod 13 has two tooth-like projections 22 and 23. Projection 22 extends to the side where the switch 19 is positioned and projection 23 extends to the side where the switch 20 is positioned. These projections move together with the rod 18 and the pedal 14. The button 21 of the switch 19 reaches into the path of the projection 22. The button 21 of the switch 20 reaches into the path of the projection 23. The projections are so arranged along the rod 18 that, when the pedal is pressed down, first the projection 22 engages and pushes the button of the switch 19. Further movement of the pedal then brings the projection 23 into operative engagement with the button of the switch 20 while the projection 22 snapping over the button of the switch 19 releases the latter button. Further movement of the pedal downward permits the projection 23 to snap over the button of the switch 20 to release this button as well. Thus the pedal has three operative positions which follow each other as the pedal is depressed, a first position operating switch 19 only, and second position operating switch 20 only and a third position releasing the operation of both switches.

Each switch serves to control the flux of either the abrasive liquid suspension or the fluxof water as a flush. For example, switch 19 controls the flux of the abrasive liquid and switch 20 controls the flux of water.

,To accomplish the suspension of the abrasive material in a liquid such as water, without causing the clogging of fine tubing, a well-known physical property of fluids must be taken into consideration.

Fluids at areas of interface between a solid or a gas, or at its surface, display a measurable force called surface tension. This force, creates a cohesive force at the points of contact of water and tubing that causes Water to sling cohesively to the sides of'tubing. In very fine tubing, this force causes the water to rise in the tube, against the force of gravity. Thisis known as capillary action. These cohesive properties of water in a fine tubing, and its surface tension at its narrow interface with a gas in a tube, provides for the physical forces which make the operation of this invention possible.

To demonstrate the principle of operation of my in vention, a stirred mixture and a fine abrasive powder, as aluminum oxide-mesh 280, is introduced into a transparent tube. Intermittent bubbles of air are allowed to enter the tube alternating with the liquid abrasive mixture. The abrasive material settles out of the water rapidly, but it settles only to the level of the entrapped air bubble. At this point, the surface tension of the water presents what is known as a meniscus, and it is able to support a heavy concentration of abrasive. Thus, the abrasive remains in the water in small increments at the level of the interface of water and air, and does not settle through the air bubble even if forcefully disturbed. In eifect, the tubing is clogged, but only in small intermittent increments, which are easily forced through the tubing when a small amount of air pressure is applied to one end of the tubing. The abrasive can thus be caused to flow freely in a fine tube and is released at its outlet alternately with the air. This physical property of water'furthers the advantage to this invention because the surface tension is greater with tubing of narrower inside diameter. For the purposes of this invention, a tubing with an inside diameter of A of an inch is best, and is, demonstrably superior to a tubing with a A: inch inside diameter.

In order to accomplish the above principle of operation, several methods may be devised. Figs. 4, 5 and 6 opgrated. by thefootfpedal and-switches described in; Figst l to 3 exemplifythe embodiment ofgthis-invention.

. Referring to Fig. 4, a source of gaseous fluid under pressure orcompressed air 31 commonly provided for in most dental ofiices, is conducted in the direction of the arrows through two conduit or duct systems 32 and 33. The duct 32 conveys the compressed air to a reservoir or container 34, which 'is a syphon type receptacle which holds a substantial amount of abrasive and water 39. A branch 35 of this duct system passes to an agitating rod,v which is operatedby the compressed air or by an electrical motor to rotate and keep the abrasive and water in .a constant state of agitation and mixture. The other branch 36 of this duct releasesthe compressed air over the volume of water and abrasive in the container 34to keep the material therein under constant pressure. Thus, the abrasive water suspension 39 is forced out of the container 34 through an outlet conduit or duct 37. From this point, the abrasive suspension flows to the inlet port of a normally closed solenoid control valve 38 which is operated by the electric circuits and foot control pedals 14 (to be described later).

When the solenoid valve 38 is energized, its ports open and the abrasive suspension is permitted to pass through to a manually operated shut-off valve or closure 40, which is normally kept open. The abrasive suspension is thus finxed to a T connection 41.

v t The compressed air duct 33 passes in the direction of I the arrow through another normally closed solenoid control valve 42. When this valve is energized 'by the electriccircuin'the compressed air is permitted to flow past a} directional flow valve 43 (the direction is indicated by anarrow). This valve43 prevents a backflow of abrasive from the T connection to the valve 42. The air in the duct 33 is thus permittedto flow to the T connection 41 where it meets the flow of abrasive suspension 39. At the outlet of the T connection 41, another manually operated shut-ofi valve or closure 44 is provided. The duct system continues through to a flexible conduit or tubing 45 in the direction of arrow 46' to its outlet nozzle (not shown) which is attached to the ultrasonic handpiece (not shown) where it is directed to flow out at the point of operation of the ultrasonic cutting tool. Tubing lines have been shortened for the sake of corn- .pact presentation.

Another conduit or duct system conveys water'from a source of Water normally provided. This duct system 49 provides water only in the direction of the arrow to the ultrasonic handpiece for the purposes of flushing the tooth orfield of operation, of accumulated'debris and abrasive material. for the purposes of better visibility. The water in this duct 49 flows to a manual faucet type valve 50 for purposes of controlling the volume and force of the water. The duct then passes to a three-way solenoid valve 51 which has a normally closed (N. C.),

a, normally open (N. O.) and a common (C.) port. When this valve is energized by the electric circuit, the water is permitted to flow through the-normally closed port through to the common port while the normally open port closes. The water is thus diverted through a duct 52 to an outlet nozzle attachedadjacent to the abrasive. nozzle. on the ultrasonic handpiece (not shown). The nozzle directs its flow to the point of operation of the ultrasoniccutting tool. a 1

;.;When the electric circuit to this valve 51 is opened, his deenergized. The normally closed port closes, while the normally open port opens, and the water in the duct 52 is permitted to drain back through the duct53 to an outlet nozzle 54, which has a very fine needle size opening. The water thus empties into a Waste receptacle or waste line 55 but the fine size of the needle permits this ply. This duct arrangement prevents the possibility of water flowing from the water-outlet nozzle 47 after the circuit to the valve is opened permitting the dentist to have complete visibility of the field of operation. Further, this duct arrangement precludes the possibility of the water dripping out of the nozzle should it be necessary to remove the handpiece from the patients mouth and thus prevents any afterdrip which may fall on the patients clothing or on the dental equipments The operation of the valves 38, 42, 51 is derived from the movement of the pedal 14 in Figs. 1-3. These valves of the solenoid type are operated by an electric circuit which is illustrated schematically in Fig. 5. This circuit is provided with a pair of terminals 59 which are connected in a well-known manner to an electric current source. The valves 38 and 42 are placed in circuit with the switch 19. The valve 51 is placed in circuit with the switch 20. When the pedal 14 is in its inoperative position of rest, the switches 19 and 20 are open, and the valves 38, 42 and 51 are closed, and noabrasive suspension or water is supplied in the direction of the arrows to the duct systems. When the pedal 14 is depressed to its first operative position, a timing device 63 is set into operation by the switch 19 for operating the suspension and air control valves 38 and 42. This timing device is essentially an electric clock provided with contact buttons which, at given intervals of time (onehalf or one second) closes the circuits to the solenoid valves 38 and 42 in an alternate manner. Thus, when the switch button 19 is pushed, the timing clock alternately closes the circuit, first to thesolenoid valve 38 in the abrasive duct system which opens; and permits a flow of abrasive suspension to the T connection 41.' At a given interval later, this circuit opens and the solenoid valve 38 closes to shut off the supply of liquid-abrasive suspension. Immediately, thereafter, the clock closes the circuit to the solenoid valve 42 which becoming energized, opens and permits a flow of compressed air to the T connection 41. The duct system 45 is thus provided with alternate increments of abrasive suspension 66 and compressed air 67 in a continuous manner as long as the pedal 14- is depressed (see the broken away portion of Fig. 2). The abrasive suspension will not settle out of the water because of the increments of air bubbles present that create at their interface the surface tension that prevents the abrasive from settling through the air bubbles as previously described. In this manner, a continuous but alternating supply of abrasive suspension is provided at the cutting endof the ultrasonic handpiece tool drainage from the duct 53 at a very slow rate so that a automatically and without the need for the dentist to interrupt the operation.

When the pedal 14 is depressed to its second operative position, the tooth-like projections of the pedal mechanism releases and permits the switch 19 to open the circuit to the timing mechanism 63. Simultaneously, the circuit operated by the switch 20 is closed and the three-way solenoid valve 51 is energized. Its ports operate in the manner previously described to supply a. fiow of water to the point of operation of the ultrasonic handpiece.

Referring to Fig. 6, which is a schematic diagram of the electric circuit system connecting the ultrasonic switch control shown in Figs. 1-3 with the electrical system controlling the electrical power supply to the ultrasonic dental handpiece. A source of electrical current is supplied to a pair of terminals 62 in' a well-known manner. This electrical network may originate in a panel installed in the panel of the ultrasonic dental unit. Dne line of the circuit 64 passes to a master switch (M. S.) installed on the ultrasonic dental unit which is a manual on-oir" toggle switch of well-known type. When this switch is off, no electrical power is supplied to the ultrasonic handpiece (not shown). When this switch is on, the movement of the lever 3 by the dentists foot in a lateral arc will push either one of the buttons of the switches 7 of Figs. 1 and 2, and close the circuit 65. Thus, the circuit to the power supply to the ultrasonic handpiece is closed and it operates in the manner heretofore mentioned.

When the need for abrasive is anticipated, the dentists foot, already in position on the pedal 14, and operating the lever 3, presses down on the pedal 14 to flux the flow of abrasive as previously described in the operation of the pedal mechanism. In a like manner, when the need for water is anticipated, the dentists foot can press the pedal 14 to its second operative position to flux a how of water for the purposes previously described. Throughout these movements, the lever 3 remains in its operative position supplying the electrical power to the ultrasonic handpiece.

Thus the dentist can easily and quickly change the position of the pedal to interrupt or flux the supply of abrasive suspension or water whenever the operation requires them, or resume the supply of either whenever he expects the need for them. Thus, Without interrupting the progress of the dental operation, he may electively dose the point of operation at will with either the cutting abrasive material or the water for flushing and visibility.

The manually operated shut-ofi valves 40 and 44 provided are for the purposes of cleaning out the duct systems in a very quick and efiicient manner, in the event that these become clogged with abrasive material, and to permit the cleaning of the duct systems if fresh abrasive be required. When the valve 4t) is closed, a flow of abrasive suspension will be prevented to the T connection 41. The closing of the circuits to the solenoid valves 38 and 42 will permit a flow of compressed air only through the duct 45. In this manner, any material in it will be blown out.

When the valve 44 is closed, and the valve 40 is opened, the closing of the electric circuit to the valves 3% and 42 will permit a flow of air through the solenoid valve 33 to blow out the valve 38 and the duct 37. In this man ner, any material in these ducts will be cleaned out.

A further provision to be made with this invention is the addition to the water and abrasive mixture in the container 34 of a fluid chemical, which is pleasant tasting, and of a non-poisonous nature that will increase the surface tension forces of water with which it can be mixed. Chemicals can be added which are non-poisonous and pleasant-tasting that increases the viscosity of water and thus enable the fluid to carry a heavier concentration of abrasives without clogging the tubing. Still other chemicals of like nature can be added that tend to lubricate the walls of the tubing and ducts so as to decrease the frictional drag of the abrasive particles on the walls of tubing and ducts, thus allowing the abrasive to pass more smoothly through these tubes and ducts. Thus with a chemical fluid of this type, a more etficient operation of this invention will be achieved.

I desire it understood that my invention is not confined to the particular embodiment shown and described, the same being merely illustrative, and that my invention may be carried out in other ways within the scope of the appended claims without departing from the spirit of my invention as it is obvious that the particular embodiment shown and described is only one of the many that may be employed to attain the objects of my invention.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. Apparatus for use with an ultrasonic dental handpiece, said apparatus comprising conduit means for conducting a liquid-abrasive suspension from a supply source to said handpiece, suspension control means in said conduit means for interrupting the flow of said suspension in said conduit means, means for feeding gas under pressure into said conduit means, gas control means in said gas feeding means for interrupting the feedingof said ga to said conduit means, and timed operating means coa nected to said suspension and gas control means for operating'the same in timed relation to effect flow in said conduit means of alternately liquid abrasive suspension and gas. g

2. Apparatus according to claim 1, in combination with conduit means for delivering a coolant to the field of operation, means for controlling the fiow of coolant in said last-named conduit means, and an actuating member selectively movable between a coolant control actue ating position and a suspension and gas control actuating position, for flushing the field of operation as desired. r

3. Apparatus for use with an ultrasonic dental hands piece, said apparatus comprising a reservoir adapted to contain a liquid-abrasive suspension under pressure, a

suspension duct communicating between said reservoir and hand-piece for conveying said suspension therebetween, a suspension control valve in said suspension duct for opening and closing communication between said reservoir and hand-piece, a gas duct communicating be.- tween a source of gas under pressure and said suspension duct intermediate said suspension control valve and handpiece, a gas control valve in said gas duct for opening and closing communication between said gas source and suspension duct, and operating means connected ,to said gas and suspension control valve for operating the same in timed relation to elfect flow in said suspension duct of alternate quantities of said suspension and gas.

4. Apparatus according to claim 3, in combination with a selectively operable closure in said suspension duct between s d h nd-v ew and h i et r o a d .5 See sion duct with said gas duct, and an additional selectively operable closure in said suspension duct between said res; ervoir and said junction, whereby said suspension d u c t may be cleaned by selectively passing gas under presspre through the last named duct on opposite sides of said gas duct junction.

5 Apparatus according to claim 3, in combination with a second gas duct communicating between said gas source and said reservoir for placing said suspension under pressure.

6. Apparatus according to claim 5, in combination with a pneumatically operable agitator disposed in said reservoir for stirring said suspension, said agitator being connected to said second gas duct for operation by gas from said source.

7. Apparatus for use with an ultrasonic dental band- 7 piece, said apparatus comprising conduit means for conducting a liquid-abrasive slurry from a supply source to said hand-piece, slurry control means in said conduit means for interrupting the flow of said sluurry in said conduit means, means for feeding a second fluid under pressure into said conduit means, control means for the second fluid, and means in said fluid feeding means for interrupting the feeding of said second fluid to said conduit means, and timed operating means connected to said slurry control and second fluid control means for operating the same in timed relation to effect alternate flow in said conduit means of said liquid-abrasive slurry and said second fluid.

References Cited in the file of this patent UNITED STATES PATENTS 1,664,369 Maurer Mar. 27, 1928 2,661,537 Angell Dec. s, 1953- 2,667,015 Berg Jan. 26, 1954 2,696,049 Black Dec. 7, 1954. 

